This invention relates to a dust container having a bag of air pervious material with an opening covered by a plate, the plate being provided with an opening through which dust laden air flows into the bag.
Dust containers of the type mentioned above are known and are currently used in vacuum cleaners to achieve a hygienic handling of the dust being collected. There are, however, a large number of different types of dust containers on the market. Each type of dust container suits one or several models of vacuum cleaners, the plate of each dust container being shaped such that it should solely suit the particular model or models that the dust container is intended for. In order to prevent the wrong dust container from being inserted into the vacuum cleaner or to prevent the vacuum cleaner from being started without a dust container, the vacuum cleaner is usually provided with sensing means connected to the electric circuit of the vacuum cleaner. The sensing means prevents dust from flowing into the fan unit and to the outlet filter, which is normally placed after the fan unit, if a dust container is not inserted. Such sensing means could be a micro switch sensing the presence of the plate or the dust container, pneumatic sensors, see GB 1494310, which are blocked by the plate when the wrong dust container is inserted or electromagnetic sensors (including optical methods) for sensing identification means on or within the dust container, see EP-A-790030.
However, all these methods have certain deficiencies. Micro switches indicate the presence of the dust container, but do not indicate whether the correct dust container is used. Pneumatic sensors and, in particular, the flow paths within the plate of the dust container, are sensitive to disturbances because of their small dimensions. Electromagnetic sensors are comparatively complicated and, thus, rather expensive.
Accordingly, there is a need in the art for a dust container that is simple to manufacture and enables the vacuum cleaner to identify the dust container so as to permit the vacuum cleaner to be started only when the correct dust container has been placed in the correct position in the vacuum cleaner. The present invention is directed to such a dust container.